Polymerization of hydrocarbons



1936-- RC. OSTER-STROM 2,063,522

POLYMERIZATION OF HYDROCARBONS Original F'iled Feb. 1, 1929 PatentedDec. 8, 1936 UNITED STATES POLYMERIZATION OF HYDROCABBONS Rudolph G.Osterstrom, Kenilworth, Ill., assignor to The Pure Oil Company, Chicago,111., a corporation of Ohio Application. February 1, 1929, Serial No.336,868

1 Renewed September 20, 1934 dcl-aims.

This invention refers to an improved method fortreating hydrocarbons,such as distillates or vapors obtained from cracking apparatus, stillsor the like, for the purpose of removing from 5 the hydrocarbons undertreatment gurmforming and color-imparting bodies, with the end in viewof securing a treated substantially gum-free motor fuel oil-of desiredcolor.

In certain'oil cracking operations, particularly high temperature vaporphase operations and to a certain extent in low temperature or liquidphase operationsyoils are produced containing a large percentage ofunsaturates that include compounds which, if unremoved, tend to discolorthe final condensate and produce gum deposits therein. These bodies,therefore, render an untreated distillate unsuitable for use as acommercial motor fuel.

In my prior application Serial No. 329,417 filed December 31, 1928, Ihave described a method of removing these undesirable bodies whichconsists generally in introducing a finely divided, solid catalyst,.such as fullers earth, to a body of oil discharged from a still,cracking apparatus or other heater, and then bringing the adsorbent intointimate contact with the oil byfforcing the latter under pressure,together with the catalyst, and while in the state of vapor through aheater, and then permitting the materials to expand under reducedpressures in a separating chamher, in order to separate the treatedvapors from the'polymerized, liquid and clay-bearing compounds.

In connection with the operation of my prior system I have observed thatin order to secure a final product having a desired gum content andcolor it is necessary when the system is first operated to employ arelatively large amount of the catalytic, contact or adsorbent material.After the system is in operation for a certain period of time it isfound that the same specifications of the end product can be secured byemploying a very materially reduced amount of the contact or catalyticmaterial as compared with thatoriginally used when the operation of thesystem is first initiated. As the run proceeds, I have.found that I canstill further reduce the amount of clay or other catalytic material useduntil after substantially seven days 50 operation I am andspecifications of the end product with about one half the quantity ofclay whichwas employed when the After the system has been in operation,careful investigation fails to reveal the presence of clay maintainingthe same quality system was originally started.-

accumulations in the system that might have a tendency to give betteraction as the run proceeds; In order to account for this condition,

I am of the opinion, although I do not definitely limit myself to thetheory, that polymerization 5 is accelerated when the material to bepolymerized contains a percentage of polymers that is, previouslypolymerized oils. The present invention, therefore, resides inintroducing into the ofl under treatment polymers inregulated 1oproportions to accelerate the polymerization of certain compoundspresent in the fresh oil undergoing treatment.

It is another object of the'invention to separately remove thepolymerized oil from the 15. treated products, and then, after removingthe clay or other treating material from the polymerized oil, to returnthe latter to the oil undergoing polymerization in the main treatingpassages or zones of the system, in order that the polymerized oil maybe employed after the manner of a catalyst, to promote polymerizationreactions of the oil under treatment and passing through the maintreating zones of the system.

By way of illustration and to more fully develop the features of thepresent invention, there has been illustrated in the accompanyingdrawing in diagrammatic form apparatus and a flow diagram by which onespecific form of the invention may be considered in detail.

Referring more particularly to the drawing, the numeral I designates acracking still, converter, reaction chamber or distillation unit. Inthis connection it will be understood thatthe invention may be used inthe purifyingof vapors released from (1) a vapor phase converter, orother high temperature cracking unit; (2) a cracking still of a liquidphase converter; (3) the reaction chamber or expander of a liquid phaseconverting system; or (4) a pipestill, 4o shell still or other source ofhydrocarbon vapor supply. In all of these operations hydrocarbon vaporsmay be produced containing undesirable compounds from a color or. gumregulation standpoint. In vapor phase systems of conversion this isespecially true, since in such systems the evolved vapors must betreated to remove therefrom gum, color, odor producing and other'compoundswhich require elimination before the end product can becommercially handled. While a cracked vapor phase distillate requirestreatment in these respects, distillates obtained from liquid phasecrackingv systems also require similar treatment as well as vaporsobtained from other heat treat ng units.

From the unit I vapors which are generated therein pass by way of a pipe2 into an evaporator 3. The materials which remain unvaporized in theunit I or which condense in the evaporator collect as liquids in thebottom of said evaporator and are withdrawn by way of the line 4. Thevapors of the evaporator pass overhead by way of the line 5 and afractionating tower 6. In this tower the liquid condensate, whichaccumulates in the bottom drum 1 is withdrawn by way of a pipe line 8 ormay be employed as recycle stock. The vapors which are released from thetop of the tower 6 are conducted by way of the pipe line 9 into thelower portion of a scrubbing tower Ill. The top of this tower isprovided with a line H bymeans of which polymer-containing oils areintroduced into the top of the tower ID for direct contact with theascending vapors passing through said tower. The source of thisdescending contact 011 will be later described. The descending oilpasses through the tower III in countercurrent relation to the ascendingvapors, intimately contacting with said vapors and removing therefromall high boiling point compounds which may be entrained in said vapors.In addition the vapors are subjected to direct contact with thepolymerized compounds contained in the reflux oil in order to removefrom the vapors the undesirable gum-forming constituents which they maypossess. The vapors pass overhead from the tower H] by way of the pipeline i2, and may be circulated through a condenser l3 and then to astorage tank H as a finally treated product.

There collects in the bottom of the tower I0 a quantity of liquefiedhydrocarbons, consisting of the polymer-containing oil introduced by wayof the line II and the condensed oils obtained from the vapors flowingthrough' the tower l0. These oils-pass from the tower I0 by way of aline I! in which is provided a control valve l6, and 'are led into apump IT, in order that said oils, together with thoroughly intermingledpolymers and clay, added at the pump l1, may be forced through a pipeline i8 leading to a coil bank is arranged within the setting of a pipestill 20.

Through the medium of the pump i1 relatively. high temperatures aremaintained on the oil under heat treatment in "the pipe still.

These pressures may be approximately 200 pounds per square inch and atthe same time the oil within the pipe still is heated to a temperatureof approximately 650 F. These temperatures and pressures have been foundto be effective in securing proper reactions in the matter of efiectivepolymerization of the undesirable gum-producing compounds. I haveobserved that the higher the temperature inthe pipe still the greater isthe efficiency of the treating process, all conditions being equal, and

for this reason I employ temperatures considerably higher than thoseused in analogous prior processes. At the temperatures and pressuresspecified the oil thus undergoing treatment remains or is maintained inthe vapor phase, the pressures and temperatures utilized being highenough to thoroughly impregnate the oil undergoing treatment with. thecatalytic compounds present therein.

After circulating through the coil bank of the pipe still, the oil ispassed through a pipe line 2| provided with a pressure release valve 22,andthence into a fractionating tower 23, where the oil vapor may bemaintained at a pressure 7 and possess a water-white color, asatisfactory odor, good stability upon exposure to light or air asregards resistance to discoloration and possess a negligible gumcontent.

This system has been generally described in my aforesaid co-pendingapplication but the present invention resides particularly in passingthe treating clay and polymerized oil through a cooler 21, connectedwith the pipe line 24, in which the oil and clay mixture is brought downto a desired temperature. The mixture is then forced by means of a pump28 through a filter 29, such as a Bweetland filter press, in which theclay or other contact material is removed from the polymerized oil. Thisoil is then forced from the oiitlet side of the filter 29 through a pipeline 30 by means of a pump or the like 3| to the pipe line H leadinginto the top of the tower Ill and into the top of the tower 6 'so thatthe polymer containing oil may come into direct contact with the vaporspassing through .the towers 6 and I0. The pipe line 32 leading from thepump 3| may be provided with suitable valves 33 for regulating the fiowand quantity of polymer-containing oil into such towers, there being atank 34 arranged in communication with the pipe line 32 for receiving anexcessive quantity of the polymercontaining 011. If finely divided clayis used in eonnection with the system such clay may be introduced intothe inlet side of the pump I! in order that it may be forced with theoil under treatment through the pipe still.

With the operation of this system I am enabled to operate quiteeconomically from a standpoint of clay consumption.- The system provides'for the maintenance of a desired amount of polymers in contact with theoil vapors undergoing purification and through the medium of the valves33 this regulation may be conveniently carried out. In certain runs,depending upon the character of the material under treatment, I havefound that the clay may be eliminated, although at present in themajority of operations I employ fullers earth or other finely dividedclays, but in a greatly reduced amount as compared with formerpractices. Insofar as I am aware, the present invention constitutes thefirst system to utilise polymer-bearing oils as catalysts or contactmaterials for facilitating polymerization reactions in other oils, and Itherefore claim this discovery in its application to purification systemof the general character above set forth.

What is claimed is:

l. The method of decolorizing and d cracked petroleum oils containinghigh percentages of unsaturated compounds which comprises: passing a.stream of such oils in a substantially vaporous state from a. crackingzone through a fractionating lone, bringing into intimate contact withsaid vapors during the 16 aoaasaa pressures through an elongatedexternally heat ed polymerizing zone of restricted cross sectional areato effect further polymerization of undesired compounds of thecondensate, withdrawing the products of the polymerizing zone andseparating the same under reduced pressure to effect the removal asvapors of the desired treated oils from the undesired high boilingpolymer containing oils, and returning a portion atleast of suchpolymercontaining oils to the fractionating zone for admixture with the crackedoil vapors passing therethrough.

2. The method of dec'olorizing and degumming cracked petroleum oilscontaining high percentages of unsaturated compounds, which comprises:passing a confinedstream of such oils in a substantially vaporized stateobtained I from a cracking zone through a fractionating zone, during thepassage of thetvapors through the fractionating zone, bringing intointimate contact therewith regulated quantities of high boiling oilscontaining polymerized petroleum bodies to effect primary polymerizationof undesired compounds present in said vapors, removing from one portionof said fractionatlng zone uncondensed oils as a treated end product,separately removing from another portion of said fractionating zone acondensate composed of relatively higher boiling oils and containingsaid polymerized bodies, introducing into the mixture of said condensateand polymerized bodies an adsorbent catalyst, subjecting this mixture tothe action of heat and pressure to effect further poly- 3 merizati'on ofundesired compounds present in the condensate, removing the-productsof'such further polymerization from the influence of heat and pressureto effect the removal as vapors of the desired treated oils from theundesired high boiling polymer containing oils, and returning a portionat least of said polymer containing oils to the fractionating zone foradmixture with va- 55 pors passing therethrough.

3. The process of recovering gasoline suitable for use as motor fuelfrom cracked hydrocarbon vapors containing light and heavy gasolineconstituents, which comprises fractionating a stream of crackedhydrocarbon vapors substantially free from constituents heavier thangasoline, in the presence of hydrocarbon polymers, to separate vapors ofa light gasoline fraction suitable for use as motor fuel and acondensedheavier gasoline fraction requiring further treatment,withdrawing said condensed heavier gasoline fraction containing saidpolymers and subject ing the mixture to elevated temperature and 'anelevated pressure not less than 200 pounds per square inch to effect apolymerization of undesirable gum-forming constituents to polymershaving boiling points above a gasoline boilingpoint range,"reducing thepressure on said treated fraction and fractionating it under the therebyreduced pressure to separate polymers, including those formed in saidtreatment, from the treated vapors, withdrawing vapors from thelast-mentioned fractionation step and condensing them to recover, thevdesired treated heavy gasoline fraction, and returning at least aportion of said polymers to the first-mentioned fractionating step;

4. The process of recovering gasoline suitable for use as motor fuelfrom cracked hydrocarbonzvapors containing light and heavy gasolineconstituents, which comprises fractionating a stream of crackedhydrocarbon vapors substantially free from constituents heavier thangasoline, in the presence of hydrocarbon polymers, to separate vapors ofa light gasoline fraction suitable for use as motor fuel and a condensedheavier gasoline fraction requiring further treatment, withdrawing saidcondensed heavier gasoline fraction containing said polymers andsubjecting the mixture to contact with a solid adsorptive catalyticmaterial atan eleto effecta polymerization of undesirable gumiormingconstituents to polymers having boil- I ing points above a gasolineboiling-point range,

reducing the pressure on said treated fraction and fractionating itunder the thereby reduced pressure to separate said catalytic materialand polymers formed in said'treatment from the treated vapors,withdrawing vapors from the fractionation step and condensing them torecover the desired treated heavy gasoline fraction, removing clay fromthe polymers separated in said last-mentioned fractionating step andreturning at least a portion of said polymers to the first-mentionedfractionating step. Y

RUDOLPH C.v OSTERS'I'ROM.

, vated temperature and under elevated pressure

